The subject matter disclosed herein relates to a method and system for ultrasonic inspection of an axle.
Nondestructive testing devices can be used to inspect test objects to detect and analyze anomalies in the objects. Nondestructive testing typically involves placing one or more probes on the surface of the test object in order to perform testing of the underlying structure. One method of nondestructive testing employs ultrasonic signals.
Generally, an ultrasonic testing system includes an ultrasonic probe for transmitting and receiving ultrasonic acoustic waves to and from a test object, and a probe cable for connecting the ultrasonic probe to an ultrasonic test unit that includes a display for viewing the test results. In an ultrasonic testing system, electrical pulses are fed from the ultrasonic test unit to an ultrasonic probe where they are transformed into acoustic pulses by one or more ultrasonic transducers (e.g., piezoelectric elements) in the ultrasonic probe. During operation, electrical pulses are applied to the electrodes of one or more ultrasonic transducers, thus generating ultrasonic acoustic waves that are transmitted to the test object to which the probe is coupled. Conversely, when an ultrasonic acoustic wave is reflected from the test object and contacts the surface of the ultrasonic transducer(s), it causes the transducer(s) to vibrate, generating a voltage that is detected as a receive signal by the ultrasonic test unit. As the ultrasonic acoustic waves pass through the test object, various reflections, called echoes, occur as the ultrasonic acoustic wave interacts with anomalies within the test object.
When testing with a single element probe, the echo signals are typically displayed on the screen of the ultrasonic test unit as an A-scan trace with echo amplitudes appearing as vertical deflections of the trace and time of flight or distance information displayed on the horizontal axis along the trace. This single element probe is often mounted on a wedge to direct the sound at a desired angle to inspect different regions of the test object. In order to inspect the full volume of the object, it may be necessary to scan the object several times using different angled wedges, which can be time consuming.
Another type of ultrasonic probe, a phased array ultrasonic probe, has a plurality of electrically and acoustically independent ultrasonic transducers mounted in a single housing. By varying the timing of the electrical pulses applied to the ultrasonic transducers, a phased array ultrasonic probe can generate ultrasonic beams at different angles, allowing the phased array ultrasonic probe to steer the ultrasonic beam at different angles through the test object to try to detect anomalies using a single wedge. The ultrasonic waves received at the various angles can be processed to produce a sector scan (or S-scan) image of the test object, allowing visual identification of any anomalies, eliminating the need to rescan the test object several times with different wedges on a single element probe. The S-scan provides a two-dimensional view of all amplitude and depth data from all of the transducers of the phased array probe corrected for the delay and the refracted angle.
Ultrasonic probes are used to inspect axles of, e.g., railway cars. A typical rail axle will include seats for mounting rotating devices involved in the operation of the railway car, including wheels. The inboard journal of the rail axle located between the wheels typically includes one or more gears, brake discs, and a cover for protecting the axle. These devices located on the inboard journal of the rail axle make ultrasonic inspection of the inboard journal by placing one or more ultrasonic probes on the inboard journal difficult and time consuming. For example, the cover of the inboard journal must be removed or otherwise disassembled to provide access to the rail axle to place the ultrasonic probe in contact with the inboard journal.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.